Numerical study on a liquid carbon dioxide energy storage system integrated with a transcritical heat pump

This study presents a novel energy storage system coupling liquefied carbon dioxide and a transcritical heat pump. The system combines significant advantages of commercial applicability and compact design. The proposed system demonstrates stable and continuous cooling and heating capabilities, precisely meeting diverse temperature regulation demands. It can leverage the peak-valley characteristics of electricity consumption, storing energy at low cost during offpeak periods and reliably discharging it during peak periods, significantly optimizing both energy utilization efficiency and cost-effectiveness. This paper provides a comprehensive description of the system’s operation and validates the thermal models of its components. A parametric analysis is conducted to explore the impact of key parameters on the system’s thermodynamic performance. Simulation results show that the coefficient of performance (COP) of the heat pump reaches 4.46 during cooling (380 kW) and 5.11 during heating (430 kW). Additionally, the system’s cycle efficiency is $62.84 \%$. These findings offer crucial insights for the system’s subsequent detailed design and optimization, and have significant implications for its potential widespread commercialization in the energy sector, contributing valuable references for the development of related fields.